program WaitTest;

{$APPTYPE CONSOLE}

{$R *.res}

uses
  Winapi.Windows,System.SysUtils,System.SyncObjs,System.Classes;

var
  time1,time2:int64;
  freq:int64;
  result:double;

type
  TCallBack=procedure;

  TWaitTestThread=class(TThread)
  private
    FEvent:TEvent;
    FReadyEvent:TEvent;
    FCallBack:TCallBack;
  protected
    procedure Execute;override;
    procedure TerminatedSet; override;
  public
    constructor Create(CallBack:TCallBack);
    procedure GetWaitTime;
    procedure WaitForReady;
  end;

{ TWaitTestThread }

constructor TWaitTestThread.Create(CallBack: TCallBack);
begin
  Inherited Create(false);
  FEvent:=TEvent.Create(nil,true,false,'');
  FReadyEvent:=TEvent.Create(nil,true,false,'');
  FCallback:=CallBack;
end;

procedure TWaitTestThread.Execute;
begin
  PulseEvent(FReadyEvent.Handle);
  while not Terminated do
  begin
    WaitForSingleObject(FEvent.Handle,INFINITE);
    QueryPerformanceCounter(time2);
    result:=1000000*((time2-time1) / freq);
    if not Terminated then FCallBack;
    PulseEvent(FReadyEvent.Handle);
  end;
end;


procedure TWaitTestThread.GetWaitTime;
begin
  QueryPerformanceCounter(time1);
  PulseEvent(FEvent.Handle);
  WaitForReady;
end;

procedure TWaitTestThread.TerminatedSet;
begin
  inherited;
  FEvent.SetEvent;
  FReadyEvent.SetEvent;
end;

procedure TWaitTestThread.WaitForReady;
begin
  WaitForSingleObject(FReadyEvent.Handle,INFINITE);
end;

procedure CallBack;
begin
  WriteLn(Format('Wait time=%f microsec',[result]));
end;

var
 WaitTestThread:TWaitTestThread;
begin
  QueryPerformanceFrequency(freq);

  WaitTestThread:=TWaitTestThread.Create(CallBack);
  WaitTestThread.WaitForReady;

  for var i := 1 to 10 do
  begin
    sleep(random(500));
    WaitTestThread.GetWaitTime;
  end;
  WaitTestThread.Free;
  WriteLn('Done...');
  ReadLn;
end.